“The light dove, cleaving the air in her free flight, and feeling its resistance, might imagine that its flight would be still easier in empty space.” 1
—Immanuel Kant, Introduction to the Critique of Pure Reason.
MY LAST POST, The View from Somewhere, seems to have been confounding for some of you. I expected it to be challenging, but I also wonder whether my attempt to avoid ‘isms’ made it difficult to see where I’m coming from. Hopefully this Platonic dialogue will give you some of the historical context I was drawing from in that discussion—but don’t expect the Symposium! And keep in mind this is a ridiculous oversimplification.
If you’re new to philosophy, you might have a hard time getting what I’m saying. That’s okay. Maybe some of what I talk about here will sit in the back of your mind like free-floating puzzle pieces waiting for you to discover where they belong.
A word of caution: Philosophers misinterpret each other all the time. Everyone has an ax to grind, a pet theory, a thing. Never take what one says about another for granted. Even the Great Immanuel Kant gets it wrong from time to time.2 So enjoy this fly-by-the-seat-of-your-pants survey of Western philosophy. But believe responsibly.
What happens to the coffee mug when no one is looking at it?
NAIVE REALIST (every single one of us when we’re not doing philosophy): The coffee mug stays essentially the same as it appears to me when no one’s looking at it. Anything that could happen to it while I’m looking at it could happen to it while no one’s looking at it.
TRADITIONAL SCIENTIFIC REALIST: How naive! The mug as it appears to you is not the same as the mug in itself, silly billy.
We can imagine the mug without its redness and without the scent of the coffee it’s holding at the moment, or with a different handle and feel, but we can’t imagine it without its mathematical properties—these belong to the mug even when no one’s looking at it.
This is known as the primary and secondary qualities distinction. We realists might quibble over what counts as a primary quality—whether to include mass, solidity, velocity, extension, position in space, and so on—but we agree that primary properties are quantitative and describe objects in themselves, independent of any observer. Secondary qualities, on the other hand, are relative to us; they don’t belong to the object itself but require a perceiver with the right kind of sensory system to bring them into existence. Colors, for instance, aren’t in things, but come about through our perception. The same goes for smells, feels, and sounds. To put it bluntly, qualities are not really real. Matter is what’s really real.3 We know the mug’s material reality by its quantitative properties, not its qualitative properties. We can know what it is in itself when no one’s looking at it by measuring it.4
TRADITIONAL IDEALIST: You guys crack me up. How will you measure the mug ‘in itself’ without perceiving it? Maybe you think you can just close your eyes and hold a ruler up to it? Good luck with that!
Clearly the mug’s extension and position in space are no more mind-independent than its qualities. You claim your mathematical abstractions grant you access to mind-independent reality, but you’ve failed to notice that your mathematical abstractions have been in your mind all along.5
CONTEMPORARY SCIENTIFIC REALIST: Hey Traditional Scientific Realist. Hey Traditional Idealist. I live in the future and we think the primary and secondary qualities distinction, which goes back to your days of materialism, is a bit old-fashioned.
TINA: Well I live the future too, Contemporary Scientific Realist, and I’m pretty sure we still believe in that distinction today. I mean, don’t we still privilege the quantitative over the qualitative? What’s so different now?
CONTEMPORARY SCIENTIFIC REALIST: Well back then we assumed reality could be reduced to some ultimate indivisible building block of the universe which we called the Atom. Of course now we’ve split the atom, so clearly we’re past that sort of thinking.
TINA: But I don’t think you’ve answered my question. Don’t we still privilege the quantitative over the qualitative?
CONTEMPORARY SCIENTIFIC REALIST: Well, sure.
TINA: Then aside from some refinements, we haven’t really moved beyond the primary and secondary qualities distinction, have we?
CONTEMPORARY SCIENTIFIC REALIST: I suppose not.
TINA: And while it’s true we’ve split the ‘atom’ with a lowercase A, we never found the ‘Atom’ with a capital A. You say we’re past that now, but where is the ultimate stuff that materialism promised?
CONTEMPORARY SCIENTIFIC REALIST: Well, Tina, forces were discovered, then Einstein showed us matter is energy—you know, E=MC²?—and we’ve since moved on to talking about fields and quantum mechanics. These days we even go so far as to say information is physical! The point is, Matter doesn’t matter quite so much anymore. The shift away from Matter is why we no longer call ourselves ‘materialists’ and instead call ourselves ‘physicalists’. Physicalism is the view that ‘everything supervenes on the physical’ or ‘there is nothing over and above the physical’.
TINA: In other words, your focus has shifted away from thing-ness to causality; you believe in scientific reductionism and a causally-closed deterministic universe.
CONTEMPORARY SCIENTIFIC REALIST: You could put it that way.
TINA: So our intentions and desires don’t cause anything to happen in the physical world, but are themselves caused by the physical world?
DAVID HUME’S GHOST: But necessary connection is nothing more than a habit of the mind!6
TINA: What was that? Did you hear something?
CONTEMPORARY SCIENTIFIC REALIST: No, I didn’t hear anything. Maybe it was a ghost!
TINA: I’m pretty sure I heard someone saying ‘necessary connection is nothing more than a habit of the mind. Which sounds a lot like Hume. He said that what’s presented to us by the world itself is nothing but a succession of events; we’re the ones who connect those events and then we mistakenly imagine the connection came from the world itself. If he’s right, I wonder what that would mean for your belief that ‘everything supervenes on the physical’?
CONTEMPORARY SCIENTIFIC REALIST: Hm. Dunno. Anyway, what were we saying before?
TINA: You were saying since physics has started talking about indeterminate particles rather than little tiny solid things, ‘materialism’ was replaced by ‘physicalism’.
CONTEMPORARY SCIENTIFIC REALIST: The main point is we don’t believe in miracles. That’s what we mean by ‘nothing over and above the physical’. We don’t believe science could have been as successful as it has been without being an accurate description of reality.
TINA: I get that, though I’m not sure I agree. After all, scientific theories can and have had empirically-equivalent rivals, leaving us to reach beyond strictly scientific principles to choose between them.7 But leaving that aside, what I don’t understand is why physicalism retains the old-fashioned materialist’s belief that everything must be explained mechanistically and reduced to efficient causes—matter in motion, essentially. Doesn’t that kind of thinking seem a bit…old school?
CONTEMPORARY SCIENTIFIC REALIST: That’s a bit complicated, Tina, and not everyone agrees on the specifics. Here, let me give you an example. In philosophy of mind a physicalist would say consciousness is a property of brains. Some of us would say subjective mental experiences are illusory, others are reluctant to go that far. There are a lot of different views on this and we’re currently hashing them out, but basically physicalists agree that consciousness can’t exist apart from its physical constituents. One way of putting it is to say when it comes to consciousness, we expect neuroscience will eventually give us the answer. In general, we all agree our best scientific theories tell us about the nature of reality.
TINA: And by reality you mean reality ‘in itself’? Mind-independent reality?
CONTEMPORARY SCIENTIFIC REALIST: Of course. What other kind of reality is there?
TINA: I don’t know much about classical physics, much less quantum mechanics, but from what I understand, the latter poses quite a challenge for mind-independence, not to mention classical reductionism. 8
CONTEMPORARY SCIENTIFIC REALIST: Well, Tina, there are different interpretations of quantum mechanics that minimize the role of the observer.
TINA: Yeah, like the Many Worlds Interpretation. But be honest. You wouldn’t take that literally, would you?
CONTEMPORARY SCIENTIFIC REALIST: If it’s true, of course I would take it literally! Wouldn’t you?
TINA: I’d sooner believe in the tooth fairy! You expect me to believe there’s another Tina in some parallel universe who’s saying exactly what I’m saying now, except she’s wearing a t-shirt that says, I Kan Even instead of I Kant Even? That would mean Twin Tina is a complete moron (even though I, clearly, am not a moron! 😜)
EPISTEMIC STRUCTURAL REALIST (contemporary scientific realism 2.0): I think I can answer this question, Contemporary Scientific Realist, if you don’t mind my cutting in here?
CONTEMPORARY SCIENTIFIC REALIST: Not at all, go right ahead.
EPISTEMIC STRUCTURAL REALIST: Ah, yes, Tina, our physics…it’s pretty weird stuff! Even so, I think we can still believe in mind-independent reality so long as we have Kantian humility9 about it. In other words, I don’t think we can claim to know the intrinsic properties of reality. Going back to the coffee mug, we don’t know what it is ‘in itself’ when no one is looking at it, but we can know the mug’s abstract mathematical structures. All I can say about the coffee mug when no one’s looking at it is that:
a) It exists in a mind-independent realm.
b) Its existence beyond our experience causes us to experience it.
c) We can know its mathematical structures, but what it is intrinsically cannot be known.10
IMMANUEL KANT’S GHOST: You call that Kantian humility!? Pah! I never said those things! I said we can’t know anything at all about the mug in itself, not even its existence! That’s a matter of faith, not reason.11
TINA: Kant! You’re shorter than I pictured in my head!
CONTEMPORARY SCIENTIFIC REALIST: Who’re you talking to, Tina? Who’s she talking to?
EPISTEMIC STRUCTURAL REALIST: I think she’s talking to herself.
CONTEMPORARY SCIENTIFIC REALIST: See, that’s where idealism gets you.
TINA: Kant, there’s no point in shouting. They can’t hear you.
IMMANUEL KANT’S GHOST: I guess that’s because they don’t believe in ghosts.
TINA: Well I don’t either!
IMMANUEL KANT’S GHOST: Sure. If you say so. Just tell ‘em what I said, Tina.
TINA (speaking for Kant’s ghost): Okay, guys, Kant agrees with Hume that causality can’t be derived from the world, but he doesn’t think it’s a mere habit of our minds or something we pick up on through experience. Rather, Kant says causality is the condition that makes our experience possible. It’s a fundamental and necessary structure of experience; experience without causality would amount to some unthinkable lawlessness.
Given that causality is a necessary condition of our experience, we can’t know whether a mind-independent reality causes our experience of it. To claim we can know anything at all about the world ‘as it is in itself’ is to reach beyond the limits of our reason.12 The entire point of the Critique of Pure Reason was to find out where that limit is so we don’t cross over it. So don’t cross the line!
Kant also wants you to know that he said Space and Time are, like causality, mind-dependent conditions of our experience that make experience possible, whereas “you philosophers-of-the-future” keep talking about “spacetime” as if Space and Time were physical things we observe out there. That’s like wearing rose-tinted glasses and declaring the world rosy, which he thinks is rather warped indeed. Or, he says, maybe this business about spacetime is meant to be taken metaphorically.13 Whatever the case, he insists we cannot know whether fundamental Space and Time or scientific-Einstein spacetime describe a mind-independent reality. He repeats: we can know nothing of mind-independence. Even it’s very existence is a matter of faith. We can have no knowledge of what lies beyond the limits of our experience. Science can only ever be the objective investigation of phenomena. We cannot climb outside our minds. 14
TINA: Thanks, Kant. I think you’re right that it doesn’t make sense to talk about Space, Time, and Causality as things in the world or as derived from the world…at least that’s what I think when I assume there is a realm of mind independence. And it’s hard not to! Honestly, you’ve shaped the way I think about…damn near everything! You’re the reason I got into philosophy! However, what I’m about to say is going to sound less like Kantian humility and more like Berkeleyian belligerence. I can’t help but wonder, why can’t we just, you know, do away with this whole mind-independent business? Our concept of mind-independence is itself dependent on our minds. And anyway, it seems to be causing conceptual problems for us. Maybe we need to stop thinking of everything as subjective and objective. Maybe reality isn’t really a matter of inside and outside, you know?
KANT’S GHOST: I think we need mind-independent reality, Tina, even if only as a limit to our understanding, even if it’s only a matter of faith. After all, we can’t talk about our representations unless there’s something they represent.
Tina: But how can we know our experiences even are representations if we can’t access what they supposedly represent?—
ONTIC STRUCTURAL REALIST: Well then, I’m most definitely not a Kantian! I say the mug in itself IS a structural-mathematical relation discoverable by science.15
KANT’S GHOST: Well, Ontic Structural Realist, your position is interesting, I’ll give you that, but you still face the problem of showing how mathematical structures constitute mind-independent knowledge. Indeed, not even our most abstract theories can be known to correspond to a mind-independent reality.
TINA: Kant, he can’t hear you either. But wait a minute, I just want to make sure I get this straight. Aside from Naive Realist, all of your views about what the mug is when no one’s looking go like this:
Traditional Scientific Realist: The mug in itself IS material and known by its mathematical properties.
Contemporary Scientific Realist: The mug in itself is whatever our best scientific theories say it is, knowable by its mathematical properties.
Epistemic Structural Realist: The mug’s intrinsic nature is unknowable, but it exists in a mind-independent reality and its existence causes us to know its structural mathematical properties.
Kant: We can’t even know that much about the mug in itself. Cause and effect are structures of our experience. A mind independent reality can’t even be known to exist, much less to cause our understanding of its structures; however, we must believe it exists as a limit to our understanding, as matter of faith.
Ontic Structural Realist: Reality IS a structural mathematical relation.
NAIVE REALIST: I’ve lost the plot.
TINA: In my last post I said the mug either turns into math or a mysterious something when no one’s looking at it. Hopefully by now we’re getting some handle on why I said that. Aside from Traditional Scientific Realist’s view that the mug turns into solid indivisible Atoms, a view that no longer applies for us, the positions above amount to:
We don’t know mind-independent reality.
Mind-independent reality is a mathematical structure.
Contemporary Scientific Realist might object to my characterization and say the mug in itself is knowable through its mathematical properties. But then what is the mug when no one’s looking at it? When faced with this concrete example, it becomes clear that the ‘whatever science says’ view is a placeholder that can’t quite answer the question.
NAIVE REALIST: Huh. So everyone’s calling me naive because I don’t think the mug turns into math or some unknowable something? Because I’m not sophisticated enough to turn what should be obvious into some great big unsolvable mystery? Man.
So, like, you think these guys actually believe what they’re saying? Like, when Kant’s going about his normal day, shopping, cleaning, eating dinner, haunting contemporary philosophers, do you think he really believes he can’t know what things are like when no one’s looking at them?
TINA: Nah. Philosophers and scientists don’t believe in their theories while they’re going about their daily lives. Most of the time, they’re just like you.
NAIVE REALIST: I kinda feel like I’m the only one here who hasn’t lost touch with real reality, you know what I’m saying?
TINA: Sure.
NAIVE REALIST: I mean, I always thought ‘physical’ meant concrete things. Things we actually touch, things that have colors and textures and—
TINA: Qualities?
NAIVE REALIST: Yeah. Qualities.
TINA: Maybe you’re onto something!
NAIVE REALIST: Philosophy makes my head hurt.
TINA: I say we ditch these guys and get a quality drink somewhere tangible.
NAIVE REALIST: Right on.
TINA: Hey, wait a minute. Where’d you get that t-shirt? Hang on now. What’s that say? I…Kan even? What the—no way. YOU’RE…
NAIVE REALIST &/OR TINA: …ME!
WHAT DO YOU THINK?
Should we privilege quantities over qualities?
Is Kant right that we’ve overstepped our limits when we say things in themselves cause our experiences of them?
Why do we still hold materialistic views on reductionism and mechanism and a causally-closed universe? Shouldn’t we be beyond that by now?
PODCAST MUSIC:
Subliminal Mind Pub, by Nick Herman. Check out his music, support indie artists!
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Enjoy “Joie de Funk” without me yakking over it:
FREE ONLINE TEXTS:
Galileo’s “Corpuscularianism”, The Assayer.
Descartes’ Meditations
Kant’s Critique of Pure Reason.
Berkeley’s A Treatise Concerning the Principles of Human Knowledge.
Hume’s A Treatise of Human Nature.
In the rest of this quote Kant draws a distinction between himself and Plato:
“…It was thus that Plato left the world of the senses, as setting too narrow limits to the understanding, and ventured out beyond it on the wings of the ideas, in the empty space of the pure understanding. He did not observe that with all his efforts he made no advance...."
Though Kant and Plato agree that experience entails a mixture of ideas (or ‘concepts’ as Kant calls them) and sense data—the mind is not a blank slate—Kant thought Plato too much of a realist about ideas. So basically Kant turns Plato’s objective ideas into subjective a priori categories of the understanding. In this quote he’s criticizing Plato for giving ideas more reality than they deserve.
I’m using the same quote to make a similar criticism against Kant, as I think he gives mind independence more reality than it deserves. In placing reality (noumena) beyond the world of experience, he leaves us in an impossible position. I agree with Kant’s criticism of his contemporaries regarding the primary and secondary qualities distinction; it makes zero sense to say mathematical reasoning gives us some special insight into a reality that exists beyond the boundary of our minds. Once the standard for reality gets set beyond our minds, there’s nothing within our minds that can escape suspicion. To arrive at mind-independent knowledge, we must subtract everything we can possibly know and assume whatever’s leftover is mind-independent reality. But what could possibly be leftover? Nothing we could possibly know. This whole project is futile. I think the notion of reality as mind independent is itself a suspicious abstraction which we take far too seriously; nothing we actually know (or want to claim to know) can possibly depend on it.
“…we cannot blame the good Berkeley for degrading bodies to mere illusion.” (CPR, Transcendental Aesthetic, B70.)
Damn, was that sarcasm, Kant? I didn’t know you had it in you!
Kant isn’t being terribly original here; everyone likes to accuse Berkeley of rejecting the existence of physical things. Never mind that Berkeley explains, over and over and over, that he’s not denying the existence of physical things; he’s denying the existence of Matter, an abstract idea:
XXXV. I do not argue against the Existence of any one thing that we can apprehend, either by Sense or Reflexion. That the things I see with mine Eyes and touch with my Hands do exist, really exist, I make not the least Question. The only thing whose Existence we deny, is that which Philosophers call Matter or corporeal Substance. And in doing of this, there is no Damage done to the rest of Mankind, who, I dare say, will never miss it...
III. …I think an intuitive Knowledge may be obtained of this, by any one that shall attend to what is meant by the Term Exist when applied to sensible Things. The Table I write on, I say, exists, that is, I see and feel it; and if I were out of my Study I should say it existed, meaning thereby that if I was in my Study I might perceive it, or that some other Spirit actually does perceive it. There was an Odor, that is, it was smelled; There was a Sound, that is to say, it was heard; a Colour or Figure, and it was perceived by Sight or Touch. This is all that I can understand by these and the like Expressions. For as to what is said of the absolute Existence of unthinking Things without any relation to their being perceived, that seems perfectly unintelligible…
IV. It is indeed an Opinion strangely prevailing amongst Men, that Houses, Mountains, Rivers, and in a word all sensible Objects have an Existence Natural or Real, distinct from their being perceived by the Understanding. But with how great an Assurance and Acquiescence soever this Principle may be entertained in the World; yet whoever shall find in his Heart to call it in Question, may, if I mistake not, perceive it to involve a manifest Contradiction. For what are the forementioned Objects but the things we perceive by Sense, and what do we perceive besides our own Ideas or Sensations; and is it not plainly repugnant that any one of these or any Combination of them should exist unperceived?
—Bishop George Berkeley, A Treatise Concerning the Principles of Human Knowledge
As Galileo puts it :
“Now, whenever I conceive of any material or corporeal substance, I am necessarily constrained to conceive of that substance as bounded and as possessing this or that shape, as large or small in relationship to some other body, as in this or that place during this or that time, as in motion or at rest, as in contact or not in contact with some other body, as being one, many, or few—and by no stretch of the imagination can I conceive of any corporeal body apart from these conditions. But I do not at all feel myself compelled to conceive of bodies as necessarily conjoined with such further conditions as being red or white, bitter or sweet, having sound or being mute, or possessing a pleasant or unpleasant fragrance. On the contrary, were they not escorted by our physical senses, perhaps neither reason nor understanding would ever, by themselves, arrive at such notions. I think, therefore, that these tastes, odors, colors, etc., so far as their objective existence is concerned, are nothing but mere names for something which resides exclusively in our sensitive body, so that if the perceiving creatures were removed, all of these qualities would be annihilated and abolished from existence. But just because we have given special names to these qualities, different from the names we have given to the primary and real properties, we are tempted into believing that the former really and truly exist as well as the latter.” —Galileo The Assayer, “Corpuscularianism”.
“The only thing left for me to examine is the existence of material things: Certainly at the very least I already know that they exist in so far as they are objects of geometrical demonstrations, seeing that in this way I conceive of them very clearly and very distinctly.” —René Descartes, Méditations Métaphysiques: Méditation Sixième [Meditation Six], AT IX, 57, pp. 173. My translation.
V. If we thoroughly examine this Tenet, it will, perhaps, be found at Bottom to depend on the Doctrine of Abstract Ideas. For can there be a nicer Strain of Abstraction than to distinguish the Existence of sensible Objects from their being perceived, so as to conceive them Existing unperceived? Light and Colours, Heat and Cold, Extension and Figures, in a word the Things we see and feel, what are they but so many Sensations, Notions, Ideas or Impressions on the Sense; and is it possible to separate, even in thought, any of these from Perception? For my part I might as easily divide a Thing from it Self. I may indeed divide in my Thoughts or conceive apart from each other those Things which, perhaps, I never perceived by Sense so divided. Thus I imagine the Trunk of a Humane Body without the Limbs, or conceive the Smell of a Rose without thinking on the Rose it self. So far I will not deny I can abstract, if that may properly be called Abstraction, which extends only to the conceiving separately such Objects, as it is possible may really exist or be actually perceived asunder. But my conceiving or imagining Power does not extend beyond the possibility of real Existence or Perception. Hence as it is impossible for me to see or feel any Thing without an actual Sensation of that Thing, so is it impossible for me to conceive in my Thoughts any sensible Thing or Object distinct from the Sensation or Perception of it. —Bishop George Berkeley, A Treatise Concerning the Principles of Human Knowledge [my emphasis].
These problems with the primary and secondary qualities distinction inspire Kant’s “Copernican turn”, as is clear in the introduction to the Critique of Pure Reason:
“It has hitherto been assumed that our cognition must conform to the objects; but all attempts to ascertain anything about these objects à priori, by means of conceptions, and thus to extend the range of our knowledge, have been rendered abortive by this assumption. Let us then make the experiment whether we may not be more successful in metaphysics, if we assume that the objects must conform to our cognition. This appears, at all events, to accord better with the possibility of our gaining the end we have in view, that is to say, of arriving at the cognition of objects à priori, of determining something with respect to these objects, before they are given to us. We here propose to do just what COPERNICUS did in attempting to explain the celestial movements. When he found that he could make no progress by assuming that all the heavenly bodies revolved round the spectator, he reversed the process, and tried the experiment of assuming that the spectator revolved, while the stars remained at rest. We may make the same experiment with regard to the intuition of objects. If the intuition must conform to the nature of the objects, I do not see how we can know anything of them à priori. If, on the other hand, the object conforms to the nature of our faculty of intuition, I can then easily conceive the possibility of such an à priori knowledge.”
“It is the constant conjunction of objects, along with the determination of the mind, which constitutes a physical necessity: And the removal of these is the same thing with chance.” —David Hume, A Treatise of Human Nature, Part IV, Sect. 5.
I’m including the next quote because it shows just how hardcore Hume was. He throws logic itself under the bus by arguing that it rests on the shaky foundation of our memory—what fools we are to think we can know anything at all!:
“It is obvious all this chain of argument or connexion of causes and effects, is at first founded on those characters or letters, which are seen or remembered, and that without the authority either of the memory or senses our whole reasoning would be chimerical and without foundation. Every link of the chain would in that case hang upon another; but there would not be any thing fixed to one end of it, capable of sustaining the whole; and consequently there would be no belief nor evidence. And this actually is the case with all hypothetical arguments, or reasonings upon a supposition; there being in them, neither any present impression, nor belief of a real existence.” —David Hume, A Treatise of Human Nature, PART III: Of knowledge and probability, Section 4: Of the component parts of our reasonings concerning causes and effects.
See Thomas Kuhn’s The Structure of Scientific Revolutions. Or The Copernican Revolution.
I’m sure there are arguments on both sides. I’m not prepared to take a side when it comes to interpreting the metaphysical implications of quantum mechanics…and I don’t have to! But in case you were wondering, this is the kind of thing I had in mind:
“What contemporary physics, especially quantum mechanics, can be expected therefore to describe is not ‘how mind-independent reality is’, as classical physics may permit one to presume. Within the domain of quantum mechanics, knowledge of ‘reality in itself’, ‘the real such as it truly is’ independent of the way it is contextualized, is impossible in principle.” —Vassilios Karakostas, Realism and Objectivism in Quantum Mechanics
Epistemic structural realism apparently has connections to a more recent (relatively speaking) Kantian revisionism. Rae Langton has a novel interpretation of Kant that turns the latter into something of a scientific realist…except that’s really not Kant.
In 1966, P.F. Strawson tried to salvage some sort of realism from Kant’s damn-near idealism in The Bounds of Sense, which he sees as a problem. He even compares Kant to Berkeley:
“The doctrine that the material and the mental constituents of the natural world are alike only appearances turns out, in the end, to bear with unequal weight on bodies and states of consciousness. Kant, as transcendental idealist, is closer to Berkeley than he acknowledges.”
Yup. Take away Kantian noumena, you have idealism similar to Berkeley’s.
For more on Kantian humility, see IEP. It’s nice to see they’ve included a more standard interpretation of Kant’s phenomena/noumena division:
“Since things-in-themselves, which are the mind-independent side of things, must not be attributed any such subjective cognitive features, their nature must be unknowable to us (CPR A246/B303). We can only know of things as they appear to us subjectively as phenomena, under our cognitive laws such as space, time, and causality (CPR A42/B59).”
Indeed. These are not mere off-hand remarks:
Space:
“We can never represent to ourselves the absence of space, though we can quite well think it as empty of objects. It must therefore be regarded as the condition of the possibility of appearances, and not as a determination dependent upon them.” (B/38-39).
Time:
“(a) Time is not something which subsists of itself, or which inheres in things as an objective determination, and therefore remains, when abstraction is made of the subjective conditions of the intuition of things. For in the former case, it would be something real, yet without presenting to any power of perception any real object. In the latter case, as an order or determination inherent in things themselves, it could not be antecedent to things, as their condition, nor discerned or intuited by means of synthetical propositions à priori. But all this is quite possible when we regard time as merely the subjective condition under which all our intuitions take place. For in that case, this form of the inward intuition can be represented prior to the objects, and consequently à priori.” § 6. Transcendental Exposition of the Conception of Time.
This is a simplified version of epistemic structural realism. For more info, check out the SEP article.
Causality must be seen as an a priori condition for the possibility of experience. Which means it is not applicable to the world as it is in itself.
Another thing to keep in mind: in this post I’m emphasizing Kant’s phenomena/noumena divide and showing how this problematizes the scientific realist’s claim on ‘things in themselves’. But Kant’s goal was not to undermine realism; quite the opposite, he wanted to save science from Humean skepticism. Hume’s ‘problem of induction’, his arguments showing that necessary connection is nothing more than a habit of the mind, were both stunning and powerful, and remain so today. Given what Kant was up against, I’d say he was massively, mind-bogglingly successful.
“It is not that through sensibility we are acquainted in a merely confused way with the nature of things as they are in themselves; we are not acquainted with that nature in any way at all. (A44/B62)”
I don’t think we can say it’s a matter of “if Kant had known about special relativity, he would have changed his mind”. That’s assuming scientific realism. Scientific theories begin with the assumption that space and time inhere in the world itself. But the question of whether space and time actually do inhere in the world itself or whether they are the conditions for the possibility of our experience is not directly addressed by science. I think Kant’s mostly right, or at least his version is preferable to debating nutty issues like this. In any case, the two versions—both spacetime and Space and Time—can just as well be referring to different things and in that way can live in harmony.
Keep in mind that for Kant, mind-independent reality, things in themselves, and the world in itself are all “noumena” which means unknowable. Utterly utterly utterly unknowable. Noumena is a negative concept, formed by abstraction:
“The division of objects into phenomena and noumena, and of the world into a mundus sensibilis and intelligibilis is therefore quite inadmissible in a positive sense, although conceptions do certainly admit of such a division; for the class of noumena have no determinate object corresponding to them, and cannot therefore possess objective validity. If we abandon the senses, how can it be made conceivable that the categories (which are the only conceptions that could serve as conceptions for noumena) have any sense or meaning at all, inasmuch as something more than the mere unity of thought, namely, a possible intuition, is requisite for their application to an object? The conception of a noumenon, considered as merely problematical, is, however, not only admissible, but, as a limitative conception of sensibility, absolutely necessary. But, in this case, a noumenon is not a particular intelligible object for our understanding; on the contrary, the kind of understanding to which it could belong is itself a problem, for we cannot form the most distant conception of the possibility of an understanding which should cognize an object, not discursively by means of categories, but intuitively in a non-sensuous intuition. Our understanding attains in this way a sort of negative extension. That is to say, it is not limited by, but rather limits, sensibility, by giving the name of noumena to things, not considered as phenomena, but as things in themselves. But it at the same time prescribes limits to itself, for it confesses itself unable to cognize these by means of the categories, and hence is compelled to cogitate them merely as an unknown something.” —Kant’s CPR, Chapter III Of the Ground of the Division of all Objects into Phenomena and Noumena
The objects of our experience can only be known after they have been ‘processed’ by the categories of the understanding (the innate structures of our minds, such as causality). Which means we can never know empirical objects outside of the categories. Here’s a little doodle from my college days showing noumena going into a “Phenomena Factory” … I have no idea what that arrow coming out the back is supposed to indicate. I imagine that “I” (or someone) must be the factory, and yet I’m not allowed to see the raw materials coming in.
There are various kinds of noumena, not just ‘things in themselves’ or ‘the world in-itself’. Noumena are not necessarily entities, as ‘things in themselves’ might imply. The term noumena also refers to certain beliefs such as the existence of God, the immortality of the soul, and free will. Kant believed these questions cannot legitimately be answered by reason, but we may be compelled to believe them anyway—we may believe God exists, but we can’t know. Same goes for the world in itself.
Ontic structural realism is not as ridiculous as it at first seems, especially since epistemic structural realism can seem…well…not much like realism at all, so why not go all the way? There’s something simpler about this view that may be compelling for some. After all, if there is no fundamental level to reality, no ultimate stuff, what else is left to the scientific realist but structure?
Also keep in mind there’s another form of ontic structural realism that says structural relations do not supervene on the intrinsic properties of the physical.
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